Production of nitroanthraquinone



patented May 3, 1932 UNITED STATES HAROLD r. srownnn, or BUFF LO, NEW YORK, ASSIGNOR T NATIONAL ANILINE & oHnMIoAL COMPANY, INC., or New YORK, N. Y., A CORPORATION on NEW YORK PRODUCTION OF NITROANTERAQUINONE NO Drawing.

This invention relates to an improved procfor the production of a nitroanth 'aquinone, more particularly dinitroanthraquinone.

The production oi anthraquinone by the condensation of o-benzoyLbenzoic acid (prepared by the condensation of phthalic anhydride with benzene in the presence of aluminum chloride) in sulfuric acid or in oleum, the isolation from the reaction-mixture of the i anthraquinone thus produced, and the subreaction-mixture resulting from the con densation of o-benZoyl-henzoic acid to a11- thraquinone in the presence of sulfuric acid or oleum, Without the isolation of the anthraquinone therefrom, is treated directly With a nitrating agent for the production of a nitroanthraquinone.

iy omitting the isolation of the synthetic antln'aquinone from the reaction-mixture, and subjecting it to nitration in the presence of the same sulfuric acid solution in which it is formed, the yields of nitroanthraquinone are increased and the quality undiminished, and in consequence a considerable saving; in the cost of its production is effected.

The invention will he further illustrated hy the following; specific example, but it Will he understood that the invention is not limited thereto. T he parts are by weight.

Exampla-l00 parts of technical o-benzoyl-benzoic acid of about 85 percent purity is added to 250 parts of vigorously stirred 26 percent oleum, and the mixture is heated, with continued stirring, at about 125130 C. for about one hour or until the formation of anthraquinone is complete. 210 parts of sull'uric acid of 100 percent strength is then added to facilitate stirring during the nitration and the mixture is cooled to about 30 C. 126.5 parts of mixed sulfuric and nitric acids, containing about 46 percent of nitric acid, is then added, keeping the temperature below about 70 C. After the addition of the mixed acids, the mixture is heated at 90100 C. for about 3 hours or until the nitration is completed. It is then poured into about 2000 Application filed June 4, 1927. Serial NO. 196,682.

parts of ice-Water, the precipitate is filtered oii', Washed with Water until substantially free fromacid, and dried. The resulting ro duct consistsmainly of 1.5 and l.'8-dinitroanthraquinone of quality suitable for use as an intermediate in the manufacture of dyestulis, and the yield is excellent. The product also contains other isomeric nitroanthraquinones and impurities.

In carrying out the process of the present invention, it will be understood that the proportion and concentration of reagents, and the conditions employed, may Vary considerably from those given in the example. For instance, in the condensation of o-b'enz'oylhelnaoic acid to anthraquinone, sulfuric "acid of about 92 to 100 percent or oleum up to about 26 percent or higher, may be employed, and temperatures varying from 100 to about 150 C. or higher may be used. As a rule, the stronger the acid or the oleum, the lower the temperature employed tor condensation. Further, instead oi addinga mixture of sulfuric and nitric acids, nitric acid or a nitrate capable of yieldingnitric acid With sulfuric acid, such as sodium or potassium nitrate, may be. employed. In general, the amount oi nitrating agent employed is about 1 to 25 percent in excess of that theoretically required to produce the desired degree of nitration, it depending largly upon the character of the impurities present in the O-loenzoylbenzoio acidemployed. As a rule,the greater the amountof impurities the greater the excess of nitric acid required.

In the claims, it Will he understood that the term sulfuric acid includes both sulfuric acid and oleum unless otherwise specified.

I claim:

1. In the nitration of anthraquinone, the

process which comprises reacting a nitrating densing o-benzoyl-benzoic acid to anthraquinone in the presence of sulfuric acid and sub ecting the resulting reaction-mixture to the action of a nitratmg agent in excess.

3. A process of producing a dinitroanthraquinone, which comprises condensing o-benzoyl-benzoic acid to anthraquinone in the presence of sulfuric acid and subsequently subjecting the resulting reaction-mixture, without isolation of the anthraquinone contained therein, to the action of a nitrating agent under conditions producing a dinitroanthraquinone.

4. A process of producing a dinitroanthraquinone, which comprises reacting a mixture of sulfuric and nitric acids with the reactionrnixture resulting from the condensation of o-benzoyl-benzoic acid to anthraquinone with sulfuric acid.

5. In the production of a mixture com arising.1.5- and 1.8-dinitroantln'aquinone, the process which comprises condensing o-benzoyl-benzoic acid to anthraquinone in the presence of sulfuric acid, and then reacting the mixture thus obtained with a n trating agent under conditions producing a mixture of 1.5- and 1.8-dinitroanthraquinone.

6. A process of producing lfand 1.8- dinitroanthraquinone in admixture, which comprises condensing o-benzoyl-benzoic acid to anthraquinone in the presence of oleum, subsequently introducing 100 percent sulfuric acid, and nitrating the mixture thus obtained by the addition thereto of a mixture of sulfuric and nitric acids containing about 46 per cent of nitric acid, the amount of said mixture of sulfuric and nitric acids being about 1 to 25 percent in excess of that required to effect dinitration.

7. In the production of 1.5- and 1.8-dinitroanthraquinone in admixtures. by the action of a nitrating agent on the reactionmixture obtained by condensing o-benzoylbenzoic acid to anthraquinone in the presence of sulfuric acid, the step comprising the addition of the nitrating agent to said reactionmixture at a temperature maintainedbelow 7 0 C. and subsequently heating the mixture thus obtained to a temperature of about 90 100 C.

8. A process of producing 1.5- and 1.8-dinitroanthraquinone in admixture which comprises condensing o-benzoyl-benzoic acid to anthraquinone in the presence of su furic acid having a concentration between 92 per cent sulfuric acid and 26 per cent oleum, adding 100 per cent sulfuric acid to the resulting reaction mixture and reacting the mixture with a nitrating agent under conditions producing a mixture of 1.5- and 1.8- dinitroanthraquinone.

9. A process for the production of nitroanthraquinones which comprises condensing technical o-benzoyl-benzoic acid to anthraquinone with sulfuric acid and nitrating the resulting reaction mixture without isolation of the anthraquinone therefrom.

10. A process for the production of nitroanthraquinones which comprises condensing technical o-benzoyl-benzoic acid with 5111- furic acid to anthraquinone and subsequently nitrating the resulting reaction mixture without isolation of the anthraquinone therefrom under conditions yielding a dinitroanthraquinone.

11. A process for the production of 1.5- and 1.8-dinitroanthraquinones in admixture, vwhich comprisescondensing technical o-benzoyl-benzoic acid in the presence of oleum to anthraquinone and subsequently without iso lation of the anthraquinone, nitrating the resulting reactionmixture with a mixture of sulfuric and nitric acids containing about A0% of nitric acid. A i

In testimony whereof 'I aflix my signature.

HAROLD T. STOWELL. 

